Gigabyte P55M-UD4 microATX motherboard for Intel Core i5/i7 CPUs

The board

Intel 5-series mATX boards make implicit sense because the CPU
architecture is such that there is no need for an IOH (Input/Output
Hub), as per X58. The IOH's main task is to facilitate the routing of
PCI-Express lanes, 36 in total, to/from the CPU via a high-speed QPI
link. The IOH is also connected to the southbridge via a regular DMI
interconnect.

LGA1,156 chips differ from their LGA1,366 brethren by integrating the
PCI-Express lanes directly from the CPU. That, then, removes the need
for an IOH and QPI link to the processor but reduces the total number
of lanes to 16. The chipset, P55 for example, connects to the CPU via
DMI, just as the X58's IOH does. In effect, the integration on LGA1156
(Lynnfield) is such that it integrates a complete northbridge to the
execution cores. Say goodbye to the IOH.

The southbridge-only 'chipset' frees up a generous amount of board real
estate, to the extent that the Gigabyte mATX isn't cluttered.

The GA-P55M-UD4 features four DIMM slots for dual-channel DDR3, two x16
PCIe mechanical slots that can be broken down to two x8 for multi-GPU
usage.

CPU layout is pretty good and it's easy to install a reference cooling
without fouling the small-ish heatsinks. The 8-pin power connector is
nicely tucked away, positioned just underneath where most PSUs will be
located.

A couple of four-pin and two three-pin header are good for cooling, too.

It also features some of Gigabyte's usual technology in the form of
dual BIOSes and a PCB with 2oz copper.

The main 24-pin connector and PATA port are also located at the edge of
the board, which makes sense.

Our sample board is equipped with a Marvell chip (88ESE9123) for SATA
6Gbps operation. However, Gigabyte has confirmed that retail 'UD4
boards will have the older JMicron JMB363 (3Gbps) controller.

Power, reset and clear-CMOS buttons are nice to see on a mATX board,
and the southbridge's heatsink is low-profile enough not to interfere
with longer graphics cards, but the reset and clear-CMOS might just be
obstructed.

The two x16 slots run off the CPU and provide both CrossFire and SLI
multi-GPU compatibility. The shorter x4 slot is pulled from the P55
chipset.

The floppy port is awkwardly placed at the bottom of the board.

Gigabyte sees fit to include 10 USB ports on the back, of which one
also serve as a board-powered eSATA port. PS/2, analogue audio (Realtek
ALC889A), FireWire400 (TI TSB432AB23), both coaxial and optical
S/PDIF-out, and Gigabit Ethernet (Realtek 811Dround off an impressive
backplane.

What we don't yet know is the price, but here's hoping for around
£100. Pair one of these up with an upcoming Core i5 750 and
4GB
of DDR3 and you should have decent change from £300.